title: Enantioselective syntheses of the proposed structures of kopeolin and kopeolone.
abstract: The first total syntheses of the proposed structures of kopeolin (1) and kopeolone (3) have been achieved from a common enantiopure chiral building block obtained by a chemoenzymatic enantioconvergent methodology. The syntheses feature two key steps: a one-pot reduction/diastereoselective protonation followed by a highly diastereoselective addition of an organocerate. The synthetic structures were fully characterized and all stereocenters were confirmed. The results show that the two previously reported structures were not assigned correctly, and suggest an initial structural misassignment during the isolation of the natural products. Thus, two revised structures, 1' for kopeolin and 3' for kopeolone, are proposed.
authors.affiliation: Aix-Marseille Université, CNRS, Institut de Chimie Radicalaire UMR 7273, 13397 Marseille Cedex 20, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Miquet
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.forename: Paul
authors.initials: P
authors.lastname: Brémond
authors.forename: Gérard
authors.initials: G
authors.lastname: Audran
mesh_terms: D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D001688:Biological Products; D012717:Sesquiterpenes; C587416:kopeolin; C587415:kopeolone
keywords: enantioselectivity; natural products; structure elucidation; terpenoids; total synthesis